diff --git a/twasm/README.md b/twasm/README.md
index c7dc833..7d0309d 100644
--- a/twasm/README.md
+++ b/twasm/README.md
@@ -10,6 +10,7 @@ I want to compile Bootler and Twasm with the Twasm assembler
 
 - [instructions](https://www.felixcloutier.com/x86/)
 - [opcodes,ModR/M,SIB](http://ref.x86asm.net/coder64.html) (no secure site available)
+- [calling conventions](https://wiki.osdev.org/Calling_Conventions); I try to use System V
 
 ### memory map